Data is transferred between constituent component devices in data networking equipment in accordance with established standards. In ATM cell transfer between one or more physical layer devices and an ATM layer device (link layer device) is effected using the existing standards known as Utopia level 1 and Utopia level 2. Utopia level 1 was designed for data transfer between one physical layer device and a link layer device. Utopia level 2 is an extension of Utopia level 1 that supports multiple physical layer devices. Sci Phy is a proprietary interface developed by PMC-Sierra Ltd. that is similar to Utopia level 2.
All of the foregoing interfaces are based upon the transfer of fixed-length packets normally referred to as cells. The signals and data formats were not designed to handle variable length packets between the data-link layer device and the physical layer device. At the present time there is no known interface in an ATM environment that will handle variable length packets.
Accordingly, it is an object of the invention to provide an interface that will accommodate the transfer of variable length packets.